1999 Chevrolet K1500 Suburban P0171 P0300



1999 Chevrolet K1500 Suburban P0171 P0300

|Trouble Code: P0171 (5.7L V8 VIN R Auto) |Print this code data[pic] |

|Fuel Trim System Lean (Bank 1) | |

• Fuel Details

• MIL Details

Trouble Code Conditions:

DTC P0101, P0102, P0103, P0108, P0135, P0137, P0141, P0200, P0300, P0410, P0420, P0430, P0440, P0442, P0443, P0446, P0449, P0506, P0507 and P1441 not set, engine started, vehicle driven at less than 85 mph at 400-3000 rpm, BARO sensor more than 74 kPa (10.7 psi), ECT sensor from 167-239ºF, IAT sensor from 4-194ºF, MAF sensor from 5-90 gm/s, MAP sensor from 26-90 kPa (3.7-13 psi), TP angle less than 90%, fuel level over 10%, and the PCM detected the Long Term fuel trim value was more than +23% for 6 seconds (i.e., a lean A/F mixture existed).

Possible Causes:

• Air leaks in intake manifold, exhaust pipes or exhaust manifold

• Fuel control sensor is out of calibration (ECT, IAT or MAF)

• Low fuel pressure (fuel filter clogged, pressure regulator failure)

• One or more injectors restricted or pressure regulator has failed

• HO2S element is contaminated, deteriorated or has failed

• Vacuum hose is disconnected, broken, leaking or loose

|Trouble Code: P0300 (5.7L V8 VIN R Auto) |Print this code data[pic] |

|Multiple Cylinder Misfire Detected | |

• MISFIRE Details

• MIL Details

Trouble Code Conditions:

DTC P0101-P0103, P0116-P0118, P0125, P0128, P0335, P0336, P0341, P0343, P0502, P0503, P1114, P1115, P1120, P1220, P1221 or P1336 not set, engine speed from 450-5000 rpm, system voltage over 10.0v, ECT sensor from 19-266ºF, fuel level over 10%, TP angle steady ( 1%), ABS, AIR, Traction Control and DFCO all "off", transmission not shifting, A/C status steady, ABS signals less than the rough road thresholds, and the PCM detected a crankshaft speed variation characteristic of a misfire in more than one cylinder.Note: If the misfire is severe, the MIL will flash on/off on the 1st trip!

Possible Causes:

• Base engine mechanical fault that affects one or more cylinders

• Fuel delivery component fault that affects more than 1 cylinder

• EVAP system problem or the EVAP canister is fuel saturated

• EGR valve is stuck open or PCV system has a vacuum leak

• Ignition system fault (a coil) that affects more than one cylinder

• TSB 03-06-04-030 contains a repair procedure for this code

• TSB 03-06-04-041 contains a repair procedure for this code

Top of Form

DTC P0171 Fuel Trim System Lean Bank 1

|NOTE |

|Applicable vehicles: |

|Escalade, Pickup (Classic), Suburban, Tahoe, Yukon (VIN C/K) |

|NPR/NQR |

DTC P0171 Fuel Trim System Lean Bank 1

|[pic] |

| |

|Click to Enlarge |

Circuit Description

In order to provide the best possible combination of driveability, fuel economy, and emission control, the vehicle uses a closed loop air and fuel metering system. While in closed loop, the VCM monitors the oxygen sensor signal voltage. The VCM adjusts the fuel delivery based on the signal voltage. The long and short term fuel values, which a scan tool can monitor, indicate a change made to the fuel delivery. Ideal fuel trim values are around 0% (128 counts); if the oxygen sensor signal indicates a lean condition, the VCM adds fuel. This results in fuel trim values above 0%. If the oxygen sensor detects a rich condition, the fuel trim values will read below 0%. This indicates that the VCM is reducing the amount of fuel delivered. The VCM sets this DTC when an excessively lean condition is detected.

Conditions for Running the DTC

• No active O2 sensor DTCs

• No active TP sensor DTCs

• No active MAP sensor DTCs

• No active EGR sensor DTCs

• No active EVAP system sensor DTCs

• No active ECT sensor DTCs

• No active MAF sensor DTCs

• Noactive IAT sensor DTCs

• No active VS sensor DTCs

• No System Voltage DTCs

• No active misfire DTCs

• Throttle position less than 70%

• Engine speed is between 575 and 4,000 RPM

• The BARO greater than 70 kPa

• The ECT is between 75 and 114°C (167-237°F)

• The MAP is between 22 and 85 kPa.

• The IAT is between 8 and 76°C (46-169°F)

• The MAF is between 3 and 85 g/s

• The vehicle speed less than 85 MPH

Conditions for Setting the DTC

The average of the short term fuel trim values over a period of 120 seconds indicates that a lean condition is present.

Action Taken When the DTC Sets

|WARNING |

|Important: To complete a trip cycle for the fuel trim diagnostic, the fuel trim diagnostic test must enable and run according to |

|the above enable criteria and the conditions for setting. A trip is not considered complete until the fuel trim diagnostic has run |

|by the VCM. |

When the current DTC initially sets, a software flag indicating an emissions related fault sets for 3 trips. The flag will clear provided the lean condition is no longer present. However, if the VCM detects the conditions for setting the current DTC during a trip while the flag is still set, the VCM turns on the MIL (Malfunction Indicator Lamp). The MIL remains on during all of the subsequent trips until the DTC has been cleared by service or the lean condition has not been detected and the conditions for checking the fuel trim have been met for 3 consecutive trips.

Conditions for Clearing the MIL or DTC

• The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.

• A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.

• Use a scan tool in order to clear the DTCs.

Diagnostic Aids

If using the diagnostic tables does not isolate the problem, try monitoring the LT fuel trim and fuel trim cell while operating the vehicle under various loads. This may isolate the condition which caused the setting of the current DTC.

A condition that causes the DTC P0300 Engine Misfire Detected may also set the current DTC; conversely an extremely lean condition which sets the current DTC can cause a misfire at idle and the DTC P0300 to set. If the cause of the current DTC cannot be determined and the DTC P0300 is also set, refer to DTC P0300 Engine Misfire Detected .

Typical Fuel Trim Values

|Control Module Leaning Fuel |No Adj. |Control Module Enriching Fuel |

|Max. Lean |DTC sets |-- |DTC sets |Max. Rich |

|-25% |-14% |0% |+20% |+25% |

The fuel trim values table indicates the typical fuel adjustment values as displayed on a scan tool. Negative values, or a rich condition, indicates that the injector pulse width is being decreased in order to lean out the fuel mixture. Positive values, or a lean condition, indicates that the injector pulse width is being increased in order to richen the fuel mixture.

Test Description

The numbers below refer to step numbers on the diagnostic table.

2. A more negative value indicates the VCM is leaning the fuel mixture (Rich condition), and a more positive value indicates the VCM is richening the fuel mixture (Lean condition).

5. Visually and physically check the items that can cause a lean condition in order to determine the cause of the DTC being set.

|Step |Action |Value(s) |Yes |No |

|1 |WARNING |-- |Go to Step 2 |Go to Powertrain On |

| | | | |Board Diagnostic |

| |Important: : Before clearing the DTCs, use the scan tool Capture | | |(OBD) System Check |

| |Info to save the Freeze Frame and Failure Records for reference. | | | |

| |The control module's data is deleted once the Clear Info function | | | |

| |is used. | | | |

| | | | | |

| |Did you perform the Powertrain On-Board Diagnostic (OBD) System | | | |

| |Check? | | | |

|2 |WARNING |20% |Go to Step 4 |Go to Step 3 |

| | | | | |

| |Important: : If any DTCs are set, except P0171 and P0174, refer to| | | |

| |those DTCs before proceeding with this diagnostic. | | | |

| | | | | |

| |Install the scan tool. | | | |

| |Idle the engine in closed loop at the normal operating | | | |

| |temperature. | | | |

| |Monitor the Long Term FT Bn 1 display using the scan tool. | | | |

| |Is the Long Term FT Bn 1 greater than the specified value? | | | |

|3 |Turn ON the ignition leaving the engine OFF. |-- |Go to Step 4 |Go to Diagnostic |

| |Review the Freeze Frame and Failure Records for this DTC and | | |Aids |

| |observe the parameters. | | | |

| |Turn OFF the ignition for 15 seconds. | | | |

| |Start the engine. | | | |

| |Operate the vehicle within the conditions for this diagnostic to | | | |

| |run, and as close to the conditions recorded in Freeze Frame or | | | |

| |Failure Records as possible. | | | |

| |Select DTC and the Specific DTC function. | | | |

| |Enter the DTC number which was set. | | | |

| |Does the scan tool indicate that this diagnostic failed this | | | |

| |ignition? | | | |

|4 |Is DTC P0174 also set? |-- |Go to Step 5 |Go to Step 6 |

|5 |Visually and physically check the following items: |-- |Go to Step 10 |Go to Step 7 |

| |The exhaust system for leaks. | | | |

| |The fuel filter for restriction. | | | |

| |The air induction system after the MAF sensor for vacuum leaks. | | | |

| |The vacuum hoses for splits, kinks, and proper connections. | | | |

| |The throttle body, intake manifold, and EGR valve for vacuum | | | |

| |leaks. | | | |

| |Idle Air Control (IAC); if a high or unsteady idle is being | | | |

| |experienced. | | | |

| |The Positive Crankcase Ventilation Valve (PCV), spring and O-ring | | | |

| |for proper installation. | | | |

| |The AIR system for proper operation (if applicable). An AIR system| | | |

| |that allows oxygen to enter the exhaust may present a lean | | | |

| |condition. | | | |

| |The fuel for excessive water, alcohol, or other contaminates. | | | |

| |VCM and sensor grounds are clean, tight and in the proper | | | |

| |location. | | | |

| |Was a problem found in any of the above areas? | | | |

|6 |Visually and physically check the following items: |-- |Go to Step 10 |Go to Step 7 |

| |Bank 1 exhaust for leaks. | | | |

| |Bank 1 HO2S 1 is installed securely and the electrical connector | | | |

| |is not contacting the exhaust system or ignition wires. | | | |

| |Any vacuum leaks that will only effect bank 1. | | | |

| |Was a problem found in any of the above areas? | | | |

|7 |Caution: Wrap a shop towel around the fuel pressure connection in |Central SFI - |Go to Step 8 |Go to Step 13 |

| |order to reduce the risk of fire and personal injury. The towel |413-455 kPa | | |

| |will absorb any fuel leakage that occurs during the connection of |(60-66 psi) | | |

| |the fuel pressure gage. Place the towel in an approved container |379-413 kPa | | |

| |when the connection of the fuel pressure gage is complete. |(55-60 psi) | | |

| |Relieve the fuel pressure. Refer to Fuel Pressure Relief Procedure| | | |

| |. | | | |

| |Install the fuel pressure gauge J 34730-1A to the fuel pipe | | | |

| |fitting. | | | |

| |CAUTION | | | |

| | | | | |

| |Caution: The fuel pump will operate for 2 seconds after you have | | | |

| |turned off the ignition. Make sure that all the fuel pipes and | | | |

| |fittings are securely fastened in order to prevent personal | | | |

| |injury. | | | |

| | | | | |

| |Turn OFF the ignition. | | | |

| |Turn ON the ignition leaving the engine OFF. | | | |

| |The fuel pump should run for 2 seconds. | | | |

| |The ignition may have to be cycled ON more than once in order to | | | |

| |obtain maximum pressure. | | | |

| |Monitor the fuel pressure with the fuel pump running. The fuel | | | |

| |pressure should be within the first specified value range. | | | |

| |When the fuel pump stops, the fuel pressure may vary slightly, | | | |

| |then it should hold steady within the second value range. | | | |

| |Is pressure within the specified value ranges and does it hold? | | | |

|8 |Start the engine. |379-413 kPa |Go to Step 9 |Go to Step 13 |

| |Idle the engine at the normal operating temperature. |(55-60 psi) | | |

| |Is the fuel pressure within the specified value? | | | |

|9 |Perform the Injector Balance Test. Refer to Fuel Injector Balance |-- |Go to Step 11 |Go to Step 14 |

| |Test with Tech 2 . | | | |

| |Was an injector problem found? | | | |

|10 |Repair or replace any items found. |20% |Go to Step 12 |Go to Step 7 |

| |Use the Fuel Trim Reset function on the scan tool. | | | |

| |Operate the vehicle in Closed Loop while monitoring Long Term FT | | | |

| |Bn 1 display. | | | |

| |The Long Term FT Bn 1 value should decrease below the specified | | | |

| |value. | | | |

| |Does the Long Term FT Bn 1 value decrease below the specified | | | |

| |value? | | | |

|11 |Replace the fuel injector. Refer to Fuel Injector Replacement . |20% |Go to Step 12 |Go to Step 7 |

| |Use the Fuel Trim Reset function on the scan tool. | | | |

| |Operate the vehicle in a Closed Loop while monitoring Long Term FT| | | |

| |Bn 1 display. | | | |

| |The Long Term FT Bn 1 should decrease below the specified value | | | |

| |Does the Long Term FT Bn 1 value decrease below the specified | | | |

| |value? | | | |

|12 |The lean condition is not present. Does a driveability symptom |-- |Go to Driveability|Go to Step 14 |

| |still exists? | |Symptoms | |

|13 |Refer to Fuel System Diagnosis . |-- |Go to Step 14 |-- |

| |Is the action complete? | | | |

|14 |Using the scan tool, clear the DTCs. |-- |Go to Step 15 |Go to Step 2 |

| |Start the engine. | | | |

| |Allow the engine to idle until the engine reaches normal operating| | | |

| |temperature. | | | |

| |Select DTC and the Specific DTC function. | | | |

| |Enter the DTC number which was set. | | | |

| |Operate the vehicle, with the Conditions for Setting this DTC, | | | |

| |until the scan tool indicates the diagnostic Ran. | | | |

| |Does the scan tool indicate that this diagnostic Ran and passed? | | | |

|15 |Does the scan tool display any additional undiagnosed DTCs? |-- |Go to the |System OK |

| | | |applicable DTC | |

| | | |table | |

[pic]

[pic][pic]

Bottom of Form

[pic]

Top of Form

DTC P0300 Engine Misfire Detected

|NOTE |

|Applicable vehicles: |

|Escalade, Pickup (Classic), Suburban, Tahoe, Yukon (VIN C/K) |

DTC P0300 Engine Misfire Detected

Refer to Engine Control Schematics Power, Ground, and DLC .

Circuit Description

The crankshaft position (CKP) sensor is the primary input to determine if misfire is occurring. Engine misfire is detected by monitoring crankshaft speed variations between cylinders. If a crankshaft deceleration occurs during a combustion or power stroke, the control module will compare this change in crankshaft speed to the previous cylinder. If the crankshaft speed change is more than a maximum allowable speed, the misfire is detected. Misfire may occur in a specific cylinder or in all cylinders randomly.

When an engine is misfiring, brief decelerations in crankshaft rotational speed will be detected by the CKP. The control module determines which cylinder has misfired based upon the camshaft position (CMP) sensor input. Misfire data is stored for each cylinder in separate accumulators. After 100 combustion events, the misfire totals are compared to a calibrated maximum number. If the misfire is excessive, this diagnostic trouble code (DTC) will set.

Conditions for Running the DTC

• If start-up ECT temperature is below minus 7°C (20° F), misfire detection is delayed until ECT temperature is more than 21°C (70°F). If start-up ECT temperature is more than minus 7°C (20°F), misfire detection begins after a 5 second delay.

• No active vehicle speed DTCs

• No active TP sensor DTCs

• No active MAF sensor DTCs

• No active camshaft sensor DTCs

• No active crankshaft sensor DTCs

• The fuel level is more than 10 percent

• The system voltage is between 11-16 volts

• The engine speed is between 450-5000 RPM

• The throttle position is steady within 2 percent for 100 ms

Conditions for Setting the DTC

The VCM detects a deceleration in the crankshaft speed characteristic of either an emission type misfire or a catalyst damaging type misfire.

Action Taken When the DTC Sets

If the VCM determines that the engine misfire is significant enough to have a negative impact on emissions, the VCM turns ON the malfunction indicator lamp (MIL) after the misfire has been detected on 2 non-consecutive trips under the same operating conditions. If the misfire is severe enough that catalytic converter damage could result, the MIL flashes while the misfire is present.

Conditions for Clearing the MIL or DTC

• The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.

• A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.

• Use a scan tool in order to clear the DTCs.

Diagnostic Aids

The Misfire Index counts the number of misfires. The scan tool can monitor the Misfire Index. There is a current and history misfire counter for each cylinder. Use the current misfire counter in order to determine which cylinder is misfiring or use the history misfire counter for misfires that are not currently present.

Many different conditions could cause an intermittent misfire.

Check for the following conditions:

• Check the IC control circuit for an intermittent short to ground.

• Check the spark plug wires and the coil wire for the following conditions:

o Ensure that the spark plug wires are securely attached to the spark plugs and the distributor cap.

o Check the wire routing in order to ensure that crossfiring is not occurring.

o If the misfire occurs when the weather is damp, the problem could be due to worn plug wires.

• Check for contaminated or a low fuel level and the following conditions:

o Check the fuel condition and quality. Dirty or contaminated fuel could cause a misfire condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

o If the fuel level is low, the fuel pump may draw air into the fuel rail, causing a stumble and possible misfire condition. Check the fuel trim numbers in the freeze frame to determine if this has occurred. It would be likely if the short term fuel number was above +20

o A restricted fuel filter can also cause a misfire.

Sticking intake or exhaust valves on engines with a misfire when cold.

Check HO2S for abnormal voltage readings.

Check for a vacuum leak as a possible cause of the engine misfire.

An intermittent may be caused by any of the following conditions:

• A poor connection

• Rubbed through wire insulation

• A broken wire inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5. The misfire is considered random on all cylinders if, while viewing the misfire fire counters in the misfire data list, the misfire seems to move to different cylinders.

6. The misfire is considered consistent if the misfire is occurring on the same cylinder(s) consistently.

7. When checking the spark at the spark plug wires, the spark should be consistent. A few sparks then nothing is no spark.

|Step |Action |Value(s) |Yes |No |

|1 |WARNING |-- |Go to Step 2 |Go to Powertrain On |

| | | | |Board Diagnostic (OBD) |

| |Important: Before clearing the DTCs, use the scan tool Capture | | |System Check |

| |Info to save the Freeze Frame and Failure Records for reference.| | | |

| |The control module's data is deleted once the Clear Info | | | |

| |function is used. | | | |

| | | | | |

| |Did you perform the Powertrain On-Board Diagnostic (OBD) System | | | |

| |Check? | | | |

|2 |Install the scan tool. |-- |Go to the |Go to Step 3 |

| |Are there any other DTC's stored? | |applicable DTC | |

| | | |table | |

|3 |Start the engine. |-- |Go to Step 5 |Go to Step 4 |

| |Monitor the misfire counters in the misfire Data list with a | | | |

| |load on the engine. Refer to Freeze Frame data. | | | |

| |Is the Misfire counter increasing? | | | |

|4 |Turn OFF the engine. |-- |Go to Enhanced |Go to Step 16 |

| |Using a spray bottle filled with water, wet down the secondary | |Ignition System | |

| |ignition system. | |Diagnosis | |

| |Start the engine. | | | |

| |Monitor the misfire counters in the misfire Data list with a | | | |

| |load on the engine. | | | |

| |Does the scan tool indicate a misfire is present? | | | |

|5 |Is the misfire random on all cylinders? |-- |Go to Step 10 |Go to Step 6 |

|6 |Is the misfire consistent on specific cylinder(s)? |-- |Go to Step 7 |-- |

|7 |Turn OFF the ignition. |-- |Go to Step 8 |Go to Enhanced Ignition|

| |Connect the J 26792 Spark Tester to the ignition wire of the | | |System Diagnosis |

| |cylinder(s) indicating a misfire. | | | |

| |Start and idle the engine. | | | |

| |Does the tester indicate spark is consistent on the tested | | | |

| |ignition wire? | | | |

|8 |Remove the spark plug(s) from the cylinder(s) that indicate a |-- |Go to Step 15 |Go to Step 9 |

| |misfire. Refer to Spark Plug Replacement in Engine Electrical. | | | |

| |Perform the Spark Plug Visual Diagnosis. Refer to Spark Plug | | | |

| |Visual Diagnosis in Engine Electrical. | | | |

| |Did you find a problem? | | | |

|9 |Install the spark plug(s) in the cylinder(s) that were not |-- |Go to Step 13 |Go to Step 11 |

| |indicating a misfire. | | | |

| |Start the engine | | | |

| |Monitor the misfire counters in the misfire Data list. | | | |

| |Did the misfire(s) change cylinder(s)? | | | |

|10 |Perform the fuel system diagnostic. Refer to Fuel System |-- |Go to Step 17 |Go to Step 14 |

| |Diagnosis . Repair as necessary. | | | |

| |Did you find a problem? | | | |

|11 |Perform the Fuel Injector Balance test. Refer to Fuel Injector |-- |Go to Step 12 |Go to Step 15 |

| |Balance Test with Tech 2 . | | | |

| |Did you find a problem? | | | |

|12 |Connect the J 34730-375 Injector Test Lamp to the cylinder(s) |10 sec |Go to Fuel |Go to Fuel Injector |

| |that indicate a misfire. | |Injector Solenoid |Circuit Diagnosis |

| |Crank the engine for the specified value. | |Coil Test | |

| |Does the lamp flash on all tested circuits while cranking the | | | |

| |engine? | | | |

|13 |Replace the spark plugs. Refer to Spark Plug Replacement in |-- |Go to Step 17 |-- |

| |Engine Electrical. | | | |

| |Is the action complete? | | | |

|14 |Physically and visually check for these conditions in the |-- |Go to Step 17 |Go to Step 15 |

| |following order: | | | |

| |Contaminated fuel. | | | |

| |Fouled or damaged spark plugs | | | |

| |Ignition coil and connections. | | | |

| |Damaged distributor cap. | | | |

| |Leaking EGR valve. | | | |

| |Restricted exhaust system. | | | |

| |VCM grounds. | | | |

| |Repair as necessary. | | | |

| |Did you find a problem? | | | |

|15 |Check for engine mechanical problems. Refer to Base Engine |-- |Go to Step 17 |Go to Diagnostic Aids |

| |Misfire Diagnosis in Engine Mechanical. | | | |

| |Repair as necessary. | | | |

| |Did you find a problem? | | | |

|16 |Perform the CKP System Variation Learn procedure. Refer to |-- |Go to Step 17 |-- |

| |Crankshaft Position System Variation Learn . | | | |

| |Is the action complete? | | | |

|17 |Using the scan tool, clear the DTCs. |-- |Go to Step 18 |Go to Step 2 |

| |Start the engine. | | | |

| |Allow the engine to idle until the engine reaches normal | | | |

| |operating temperature. | | | |

| |Select DTC and the Specific DTC function. | | | |

| |Enter the DTC number which was set. | | | |

| |Operate the vehicle, with the Conditions for Setting this DTC, | | | |

| |until the scan tool indicates the diagnostic Ran. | | | |

| |Does the scan tool indicate the diagnostic Passed? | | | |

|18 |Does the scan tool display any additional undiagnosed DTC's? |-- |Go to the |System OK |

| | | |applicable DTC | |

| | | |table | |

[pic]

[pic][pic]

Bottom of Form

[pic]

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download